The present invention relates generally to packaging, and more specifically to packaging with low thermal resistance.
The trend within the electronics industry is to provide increased computing power. However, increased computing power is making thermal management increasingly important. Higher device performance can create higher temperatures and lower reliability if thermal considerations aren't considered. Each calculation by each transistor, which can number in the millions, is accompanied by the generation of heat.
Although computing devices are increasing in computing power, the sizes of the computing devices are also shrinking. This can enable placing the computing devices closer together on smaller boards that helps decrease overall system size and cost, and can also improve electrical performance. Although these benefits are important, from a thermal standpoint raising power while reducing size is a bad combination.
One technique employed to reduce thermal resistance of a package such as a printed circuit board (PCB) is to use a ball grid array (BGA) such as a plastic ball grid array (PBGA). BGA packages have a plurality of solder balls located on a bottom external surface of a package substrate. The solder balls are reflowed to attach the package to a printed circuit board. An integrated circuits (IC) is mounted to a top surface of the package substrate, and electrically coupled to the solder balls by internal routing within the package. However, even a BGA package may have insufficient thermal impedance. For example, the number of solder balls is limited by the physical area of the bottom of the substrate. Thus, it would be desirable to provide a BGA package that has a lower thermal impedance than BGA packages of the prior art.